1. Field of the Invention
This invention relates to pans configured for the collection of condensate and other fluids while positioned under a heavy furnace, air conditioning unit, or other fluid-causing unit presenting a risk of fluid damage to its surroundings, specifically to a fluid-collecting tray or pan (to simplify the following description only the term “pan” will be used hereinafter, since for purposes of this disclosure the terms “pan” and “tray” are considered interchangeable) of sturdy construction that is configured and used in fluid collection and overflow prevention applications for long term and stable support of a heavy unit or system posing a risk of fluid damage to its surroundings. Its main strength-enhancing features are large upwardly-extending egg-shaped supports integrated into the pan's interior bottom surface, which extend substantially across the length and width of the pan for broad distribution of a supported unit's weight throughout much of the pan. Since the egg-shaped supports are upwardly-tapering and hollow, they facilitate compact nesting of multiple pans in stacked array. Other strength-enhancing features that may be optionally included with the egg-shaped supports as a part of the present invention pan in any combination, include an upwardly-tapering protrusion associated with each egg-shaped support that in combination with the elliptical base thereof forms a substantially triangular configuration (although the perimeter edges of the triangular configuration remain arcuate) to broaden weight distribution of the supported unit further across the pan's bottom surface and help prevent collapse of the hollow egg-shaped supports under heavy load; an arcuate annular ridge extending around the base of each egg-shaped support and its associated protrusion that also broadens weight distribution of the supported unit further across the pan's bottom surface; stress-transmitting ribs extending between at least some of the annular ridges; gussets associated with the perimeter wall that have staggered interior-projecting front edges configured to minimize the formation of stress lines in the pan during pre-installation handling and after a heavy fluid-causing unit is placed upon it, a horizontally-extending rib integrated into the perimeter wall between adjacent gussets; angled corners at the base of the perimeter wall configured to reduce stress points; an up-turned perimeter lip associated with the top edge of the perimeter wall that enhances strength and also increases fluid collection capacity for overflow prevention applications; a quick-mounting shelf associated with the perimeter wall that is configured for prompt and easy float switch installation; and an arcuate ribbed area configured to protect a float switch associated with the pan from side impact directed toward the pan's perimeter wall. Stable support of a fluid-causing unit that poses a fluid damage risk to its surroundings is also facilitated in the present invention by an indentation in the top surface of each egg-shaped support that is configured to receive at least one vibration isolator, which collectively provide safety-enhancing contact between the egg-shaped supports and the bottom surface of the supported unit for weight distribution management that reduces the opportunity for the supported unit to move relative to the pan after installation, and thereby lessens the likelihood of unit vibration shifting it during routine operation from its original position and causing premature pan failure or collapse. Multiple vibration isolators in a vertically stacked array may be used to adjust the supported unit to an optimum working height, and when they are made from (or adapted with) non-combustible materials, vibration isolators can be used to meet non-combustible clearance requirements in furnace applications. Vibration isolators also provide the additional advantage of enhanced heat deflection around a supported unit.
The primary use contemplated for the present invention pan is the combination of support for a heavy furnace or other unit capable of fluid discharge, fluid leaks, or condensation build-up at an installation site, and fluid overflow prevention at that site, wherein if the usual pathway for fluid discharge becomes blocked and causes fluid to accumulate in the pan, and thereafter rise above a pre-determined level considered safe, a float switch associated with the pan's perimeter wall will deploy and promptly send a shut-off signal to the supported unit to stop its operation, thereby preventing damage to the unit and/or its surroundings. An equally important use of the present invention pan is management of the routine cycles of fluid accumulation and evaporation expected in the pan during its support of a system or unit that at least periodically produces condensate as a by-product of its operation, perhaps as a result of inadequate insulation, so that collected fluid is not subject to localized pooling that could lead to sagging or buckling of the pan and perhaps result in its premature failure, or if a float switch is associated with the pan, and further so that collected fluid does not accumulate for extended lengths of time around the float switch to cause its malfunction or premature shut-off of the supported fluid-causing unit. Primary objectives and advantages of the egg-shaped strengthening structure disclosed herein are the providing of fluid collection and drain pans that facilitate pan installation to make it simpler and easier than that required for most prior art pans used in similar fluid collecting application, minimize the need for post-installation inspection and maintenance of the pans and any shut-off switches mounted on their perimeter walls, shorten the installation time of pans and shut-off switches, provide stable and reliable pan and shut-off switch installations, reduce the number of cracks and weak spots created as a result of pan handling prior to and during its installation, and reduce the likelihood of pan collapse due to unbalanced weight distribution when fluid accumulates in the pan during routine use.
2. Description of the Related Art
When air conditioning condensate and other condensates are collected, there is often a risk of overflow or back-up into the system producing it. As a result, a fluid collection and/or drain pan is typically placed under the condensate-producing unit with a liquid-level float switch mounted on the pan that sends a shut-off signal to the source of condensate flow to stop its operation when the amount of fluid collected exceeds a predetermined depth considered safe. If installed in an attic, on hot summer days a fluid collection pan under a condensate-producing unit can be subjected to temperatures exceeding 140-degrees Fahrenheit, which has led to perimeter wall lean-in and float switch malfunction in many prior art pans. In the alternative, an installation site can expose a fluid collection pan to significant temperature fluctuations or be a tight space that requires the installer to bend, twist, and/or step on the pan at least once before installation is complete. If the pan's materials and design are thin and/or weak in any way, cracks and weak spots can result that increase the likelihood of premature pan failure, or total pan collapse. Pans installed for support of furnaces and other units responsible for fluid damage risk to their surroundings are also subject to temperature and space limitation issues, and in addition furnace installations typically require a designated amount of non-combustible clearance. Through its use of selected materials that are chosen for their strength and temperature resistance as well as high impact resistance and corrosion resistance, a structured design chosen for its strength-enhancing properties, and a design selected because it helps to evenly pull plastic during pan manufacture so that thin and weak areas are avoided that would otherwise create pressure points when the finished material is inadvertently bent or twisted, the present invention is able to provide a pan for collection of condensates and other fluids resulting from the operation of a fluid-causing unit placed upon its egg-shaped supports that is superior to prior art pans in multiple ways, including being more rugged than most other prior art fluid collection pans, having a sturdy construction that facilitates pan installation, reduces installation time, provides stable pan and float switch installation, reduces the number of cracks and weak spots, created by pre-installation handling of the pan, reduces the possibility of pan collapse due to unbalanced weight distribution when fluid accumulates in the pan, minimizes post-installation inspection and maintenance of pan and the shut-off switch mounted on its perimeter wall, and when a quick-mounting shelf is a part of the present invention pan's perimeter wall structure, float switch mounting on the pan's perimeter wall has the advantage of being prompt and requiring no guess-work relating to placement of the shut-off switch in a level orientation since the easy step of leveling the pan simultaneously places the float switch into a level orientation for immediate, reliable, repeat, and reproducible deployment of a fluid-level-activated float body whenever fluid accumulating in the pan exceeds the pre-established (or custom-set) threshold amount considered safe to prevent damage to surroundings. Another advantage of present invention pan structure over that of some prior art pans is that present invention pan structure allows for even flow of collected fluid throughout its bottom surface, preventing the localized pooling of fluid in any one area including the area around the float switch. By preventing the float switch associated with it from remaining in contact with accumulated fluid, there is a reduced likelihood for it to become clogged with mold, algae, and/or debris, which could otherwise cause it to malfunction. Another problem overcome by the present invention pan is the likelihood of pan failure resulting from cracking, bowing, distortion, bending, warping, buckling, and/or collapse due to fluid distribution imbalance, particularly when it is supported upon blocks, trusses, or other discontinuous surface. This is accomplished in the present invention pan through its integrated structural features that avoid extended stress lines, including the curved surfaces of the annular ridges and egg-shaped supports, the curved surfaces of the vertically-extending protrusions associated with the egg-shaped supports, the staggered interior-projecting edges of the gussets, the use of angled corners, the placement of stress-transmitting ribs between some of the egg-shaped supports in close proximity to one another, and the use of vibration isolators in top indentations of the egg-shaped supports which retain the heavy fluid-causing unit resting upon them substantially in its original position during routine use. Further, the non-combustible clearance required in furnace applications can be met through use of one or more vibration isolators, in stacked array if needed, upon the tops of the egg-shaped supports, which can be made from non-combustible material or otherwise covered or adapted to meet the non-combustible clearance requirement. No other fluid collection or drain pan is known that functions in the same manner as the present invention, has the egg-shaped structure disclosed herein, or provides all of the advantages of the present invention.